Rotavirus Vaccine Effectiveness Against Hospitalization for Rotavirus Gastroenteritis in Children Under 5 years: A Test-Negative Study in Southern Italy, 2018–2025

Individual-level evidence on rotavirus vaccine effectiveness (VE) against hospitalization is scarce in Italy. This study estimated VE against hospitalization for laboratory-confirmed rotavirus gastroenteritis (RVGE) among children younger than 5 years in southern Italy. A test-negative case–control study was conducted within active hospital-based surveillance in all four pediatric inpatient wards of the Foggia District, southern Italy, from April 2018 to December 2025. All children aged 75 days to 59 months admitted with acute gastroenteritis were routinely tested for rotavirus; cases tested positive and controls negative. Vaccination status at admission was retrieved from the regional Immunization Information System; only doses given ≥ 14 days earlier counted. The primary exposure was full vaccination (two doses of the monovalent vaccine [RV1] or three doses of pentavalent vaccine [RV5]) versus none; receipt of at least one dose, vaccine product and age group were secondary. VE was estimated as (1 − adjusted odds ratio) × 100 from logistic regression adjusted for sex, age, nationality, residence, underlying conditions, and calendar period. Of 1116 admissions (1059 children), 124 were rotavirus-positive and 992 rotavirus-negative. Full vaccination was recorded for 22.6% of cases and 42.1% of controls (adjusted VE 73.5%; 95% confidence interval (CI) 57.6–83.4%); adjusted VE for at least one dose was 68.8% (95% CI 53.4–79.1%). After full vaccination, adjusted VE was 69.5% (95% CI 45.1–83.0%) for RV1 and 78.0% (95% CI 58.1–88.5%) for RV5. Age-stratified adjusted VE was 82.1% (95% CI 63.6–91.2%) in children aged < 24 months and 61.1% (95% CI 23.8–80.2%) in those aged 24–59 months. Completion of the recommended rotavirus vaccination schedule was associated with substantial protection against hospitalization for laboratory-confirmed RVGE in children younger than 5 years. These findings support improving rotavirus vaccination coverage and maintaining hospital-based surveillance.